Example of a 3D analysis for simulated sources with point-like, Gaussian and shell-like morphologies. The simulation uses “prod5” IRFs from CTA (Cherenkov Telescope Array Observatory & Cherenkov Telescope Array Consortium 2021). The left image shows a significance map (using the Cash statistics) where the three simulated sources can be seen. The middle figure shows another significance map, but this time after subtracting the best-fit model for each of the sources, which are displayed in black. The right figure shows the contribution of each source model to the circular region of radius 0.5° drawn in the left image, together with the excess counts inside that region.